Giambattista laura



G. LAURA. GALVANIG BATTERY ELEMENT.

No. 580,497. Patented Apr. 13, 1897.

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GIAMBATTISTA LAURA, OF TURIN, ITALY.

GALVANlC-BATTERY ELEMENT.

SPECIFICATION forming part of Letters Patent No. 580,497, dated April13, 1897. Application filed February 27, 1895. $erial No. 589,855.(ModeL) Patented in England February 27, 1895, No. 4,245,- in

France February 2'7, 1895, No. 245,419; in Italy February 27, 1895,

February 28, 1895,1Io. 84,715.

XXIX, 38,258, and LXXV, 105, and in Germany To all whom it may concern.-

Be it known that I, GIAMBATTISTA LAURA, a subject of the King of Italy,residing at Turin, in the Kingdom of Italy, have invented certain newand useful Improvements in Galvanic-Battery Elements, (for which I haveobtained Letters Patent in England, dated February 27, 1895, No. 4,245;in Germany, dated February 28, 1895, No. 84,715; in France, datedFebruary 27, 1895, No. 245,419, and in Italy, dated February 27, 1895,Vol. XXIX, No. 38,253, and Vol. LXXV, No. 105;) and I do hereby declarethe following to be a full, clear, and exact description of theinvention, such as will enable others skilled in the art to which itappertains to make and use the same, reference being had to theaccompanying drawing, and to letters of reference marked thereon, whichforms a part of this specification.

My invention has relation to double fluidcells for galvanic batteries,and more particularly to the copper and zinc cells.

The double fluid-cells as heretofore constructed present seriousdifficulties, which consist, chiefly, in a speedy polarization,consequently in a rapid reduction in the intensity of the currentgenerated; ina comparatively large consumption of sulfate of copper andof zinc in the care and attention such elements require; in the cost ofconstruction and in the costs arising from frequent unavoidable repairs,and in the inconvenience of transporting or shipping these elements,owing to their peculiar form and liability to breakage.

My invention has for its object to obviate these difficulties, and thisI attain as follows: by separating thev cathode from the anode fluid bya diaphragm that is impermeable to the salts of the metals held insolution in said liquids, whereby the electrolytic decomposition of thesalt in" the cathode liquid is absolutely prevented; by electrically orconductively connecting the two liquids through the medium of aconductive substance combined or intimately mixed with the diaphragm,whereby osmotic action or osmotic currents are avoided and the constancyof the cell insured; by the use of a depolarizing agent wherebypolarization is avoided and am enabled to construct cells of differentintensities according to the requirements or .conditions of use, thatthe primary cost and cost of maintenance of a cell constructed inaccordance with my invention is trifling, so to speak, when comparedwith the like costs of efficient double fluid-cells as heretoforeconstructed, while cells of my invention require practically noattention for long periods of time, in contradistinction to the constantattention required to maintain the required efficiency of cells asheretofore constructed. Finally, my improved double fluid-cell is ofsuch a construction to enable any one of ordinary intelligence toconstruct or reconstitute the same whenever this becomes necessary,while such reconstitution is necessary only after a lapse of timeproportionate to total energy developed by the cell, generally aboutonce a year.

The essential difference between my improved cell and those heretoforeused is that in the latter osmotic action generally takes place, so-called osmotic currents being produced, while in the cell underconsideration electric energy is excited solely by the difference oftension between the two electrodes, and this enables me to use adiaphragm of the simplest construction. On the other hand, I believe Iam the first to arrange the electrode-cells one above the other, dividethe same by a diaphragm impermeable by the salts of the metals in eitherchamber, and connect the liquids in the chambers electrically or conductively,by which arrangements In any of the defects inherent to doublefluid-cells heretofore used are avoided.

In a long series of experiments, particularly with starchy substances, Ihave found that none would answer the purposes in view except thosederived from the plants of the order of llfalracecc, because of theslight hygroscopic properties of starchy substances in general ascompared with the great hygroscopic powers of those derived from theplants of the order of ltlalvacccc, which even when reduced to an almostimpalpable powder still greedily absorb liquids, and which, when kneadedwith a liquid, swell considerably and form a medium impermeable by asubstance held in solution in a liquid.

I have stated above that in my improved cell there is no osmotic action,the electric energy being due to the diiference in the tension of theelectrodes, and that the liquids in the electrode-cells are electricallyor conduct ively connected. The latter feature I attain by saturatingthe diaphragm, as well as its supporting-bed, if such is used, andhereinafter to be described, by a conductive substance, as, forinstance, a solution of sodium chlorid, the pulverized Maloacete, as anAlzfhcea, (hollyhock, marsh-mallow, or rose of Sharon,) being convertedinto paste by kneading with a saturated solution of such liquid; butthat my invention may be fully understood I will describe the same indetail, reference being had to the accompanying drawing, which shows aconstruction of double fluid element embodying my invention by avertical section.

V indicates a vessel of any suitable material and form in cross-section,preferably of glass and of cylindrical form in cross-section, andprovided at a suitable point above its bottom with aninwardly-projecting annular shoulder o for the support of the diaphragm.

G is the copper or negative electrode, in this case of discoidal form,resting upon the bottom of the vessel, and having soldered or otherwisesecured thereto one of the conductors c, the vessel V being divided intotwo electrode-chambers by a diaphragm which, I may say, is absolutelyimpermeable by the sulfate of copper.

In the construction or assembling of the parts of the elementa coarsesufficientlystout textile fabric of the same outer configuration as theinner configuration of the vessel V, in the case in point of circularform, is provided with a central aperture and with a peripheralstiffener d, as a strip or piece of cane or other sufficiently flexiblematerial that will remain unaffected in the solution of sulfate ofcopper. This textile supporting-diaphragm D is first threaded upon anopen-ended cylinder or tubet of any suitable material, preferably glass,the lower edge of which is scalloped or otherwise recessed, so as toestablish communication between the interior of such tube and thecathode-chamber, when said tube is set upright on the cathode O, and inorder that a good fit of the diaphragm D upon the tube may be obtained Ipreferably make the central aperture of said diaphragm of slightly lessdiameter than the outer diameter of the tube t. After the diaphragm isfitted on the tube 25 and theco'nductor c threaded through the same saidtube is placed on end upon the lower electrode 0 and the diaphragm D isadjusted so that its stiffened or reinforced periphery d will be firmlyseated upon the shoulder Q) of vessel V. A layer of a mixture of sawdustand sodium chlorid is now placed upon the diaphragm D and suitablypacked thereon, after which a similar diaphragm D is threaded upon theglass tube'and firmly and evenly pressed upon the porous diaphragm ofsawdust S, and then the impermeable diaphragm A of a paste of Alt/icedpowder is applied to the second diaphragm D, firmly and evenly packedthereon and about the central tube, and covered by a third diaphragm Dof textile material, after which the zinc or positive electrode Z, whichin the case in point will also be of discoidal form in conformity withthe vessel V, is threaded on the tube 6, said electrode being providedwith a central aperture of greater diameter than that of said tube 15,and placed on diaphragm D The zinc electrode Z is provided with a post2, to which the other conductor 01 is connected. A solution of sodiumchlorid is now poured into the anode-chamber, while the cathode-chamberis supplied with a solution of sulfate of copper sufficient to saturatethe diaphragm D and fill the chamber between it and the bottom of thevessel V.

The supply of sulfate-of-copper solution to the element is maintained bythe use of a storage vessel B, having preferably or conveniently theform of a Florence flask, whose neck dis of such length that when thevessel is inverted into the tube 6 the latter will support the same withthe outlet at a proper distance from the cathode C, the discharge fromthe flask taking place through a tube or tubes 50 a: of comparativelysmall interior diameter, whose outer end dips into the solution in thecathode-chamber, as shown.

It is necessary to the proper working of the element that there shouldbe no air-cushion between the solution in the cathode-chamber and thetextile diaphragm D and that the air should be expelled from the latter,this being, in fact, the only care that has to be taken in assemblingthe parts of the cell irrespective of the proper packing of thematerials constituting the diaphragms S and A, while such air can bereadily expelled by supplying the cathode-chamber with sufficientsolution to saturate the textile diaphragm, a slight excess of solutionbeing in no way detrimental to the good working of the cell. The supplyof an excess of solution of sulfate of copper to the cathode-chambermay, however, be readily obviated if the solution is introduced beforethe diaphragm D and tube 25 are inserted, as any excess of said solutionwould then be forced into said tube in packing the material for thediaphragm S.

hen the diaphragm A is of considerable thickness, as shown in thedrawings, it is advisable not to pack the sawdust bed too firmly,

so that it may readily become saturated with the cathode solution andthis latter brought into contact with the Alihccct diaphragm A.

I have found that the electromotive force of an element constructedaccording to my invention can be made to reach 0.8 volts, While itsinternal resistance may be varied at Will. In my experiments I haveconstructed cells having an internal resistance varying from five to 0.5ohms, of an intensity varying from 0.1 to one ampere and of a constancythat is astonishing, as I have not detected any variation either in theelect-romotive force or in the internal resistance of one of my elementskept continuously short-circuited for a period of fourteen days.

Having thus described my invention, What I claim as new therein, anddesire to secure by Letters Patent, is-- 1. The herein-describeddiaphragm for double liquid-cells, consisting of a paste composed of apulverized plant of the order of Maloacecc and a conductive substance,as a solution of sodium chlorid, for the purpose set forth.

2. The herein-described diaphragm for double liquid-cells consisting ofa paste composed of pulverized Althma and a conductive substance as asolution of sodium chlorid, for the purpose set forth.

3. A double liquid element comprising a vessel, a diaphragm composed ofa paste made of a pulverized plant of the order of the llfaloacece, asAlthcea, and a conductive substance as a solution of sodium chlorid, anda more or less porous supportingbed for said diaphragm, for the purposeset forth.

4. A double liquid-cell comprising a vessel, a horizontal diaphragm madeof a paste of a plant of the order of the Maloacece, an d a conductivesubstance as a solution of sodium chlorid, a suitable cathode in theloWer chamber of the vessel, an open-ended cylinder extendingfluid-tight through the diaphragm into said cathode chamber and asuitable anode supported from the diaphragm, for the purpose set forth.

5. A double liquid-cell comprising a vessel, an axially horizontalperforated diaphragm consisting of a paste made of a pulverized plant ofthe order of llfaluacece and a conductive substance as sodium chlorid, amore or less porous axially-perforated bed for said diaphragm, said bedcomposed of an absorbent and a conductive substance, as a solution ofsodium chlorid, in combination with suitable electrodes in saidchambers, and an openended cylinder of greater length than the height ofthe vessel extending fluid tight through the diaphragm and its bed intothe lower electrode-chamber, for the purpose set forth.

6. A double liq uid-ce1l comprising a vessel, an axially-perforatedhorizontal diaphragm consisting of a paste made of a pulverized plant ofthe order of lVIaZoacecc and a conductive substance as a solution ofsodium chlorid, a more or less porous axially-perforated bed for saiddiaphragm, said bed composed of an absorbent and a conductive substance,as sodium chlorid, in combination with suitable electrodes in saidchambers, an open-ended cylinder of greater length than the height ofthe vessel extending fluid-tight through the diaphragm and its bed intothe lower electrode-chamber, and a storage-chamber havin g substantiallythe form of a Florence flask seated on said cylinder and provided in itsclosed neck with a discharge tube or tubes, for the purpose set forth.

7. The vessel V having near its bottom an inwardly-projectingseat-flange, a textile diaphragm seated on said flange, a bed of aporous material saturated with a conductive agent, as a solution ofsodium chlorid on said diaphragm, a second textile diaphragm on saidporous bed, a diaphragm composed of a paste made of a pulverized plantof the order of lVIaloacece and a conductive substance on said seconddiaphragm,and a third textile diaphragm, in combination with anopen-ended cylinder extending fluid-tight through the above-mentioneddiaphragms and porous bed into the chamber below said bed, for thepurpose set forth.

In Witness whereof I have hereunto signed my name in the presence of twosubscribing Witnesses.

GIAMBATTISTA LAURA. WVitnesses:

HUGO PIZZOTTI, ANTONIO MELLOY.

